Glutamate release from astrocytes as a non-synaptic mechanism for neuronal synchronization in the hippocampus
Abstract
Synchronization of activity of anatomically distributed groups of neurons represents a fundamental event in the processing of information in the brain. While this phenomenon is believed to result from dynamic interactions within the neuronal circuitry, how exactly populations of neurons become synchronized remains largely to be clarified. We propose that astrocytes are directly involved in the generation of neuronal synchrony in the hippocampus. By using a combination of experimental approaches in hippocampal slice preparations, including patch-clamp recordings and confocal microscopy calcium imaging, we studied the effect on CA1 pyramidal neurons of glutamate released from astrocytes upon various stimuli that trigger Ca2+ elevations in these glial cells, including Schaffer collateral stimulation. We found that astrocytic glutamate evokes synchronous, slow inward currents (SICs) and Ca2+ elevations in CA1 pyramidal neurons by acting preferentially, if not exclusively, on extrasynaptic NMDA receptors. Due to desensitization, AMPA receptors were not activated by astrocytic glutamate unless cyclothiazide was present. In the virtual absence of extracellular Mg2+, glutamate released from astrocytes was found to evoke, in paired reco...Continue Reading
References
Citations
Rapid elevation of calcium concentration in cultured dorsal spinal cord astrocytes by corticosterone
Altered vesicular glutamate transporter expression in the anterior cingulate cortex in schizophrenia
Related Concepts
Related Feeds
Astrocytes & Neurodegeneration
Astrocytes are important for the health and function of the central nervous system. When these cells stop functioning properly, either through gain of function or loss of homeostatic controls, neurodegenerative diseases can occur. Here is the latest research on astrocytes and neurodegeneration.
Calcium & Bioenergetics
Bioenergetic processes, including cellular respiration and photosynthesis, concern the transformation of energy by cells. Here is the latest research on the role of calcium in bioenergetics.
Astrocytes
Astrocytes are glial cells that support the blood-brain barrier, facilitate neurotransmission, provide nutrients to neurons, and help repair damaged nervous tissues. Here is the latest research.